Studies On Seeds Of Rheum Palmatum L

In this article, with Chinese traditional medical herb Rheum palmatum as material,The seeds treatment,The best harvest time and Storage conditions of Rheum palmatum were studied. The main results are as follows:1. Six kinds of chemical reagents were selected to dealt with Rheum palmatum seeds.The main results were as follows.The seeds treated by 0.3%-0.7% Potassium dihydrogen phosphate(KH₂PO₄) and Calcium chloride(CaCl₂) showed higher germination rate and germinating viability than the contro1, the seeds of Rheum palmatum could early germinated, and seedling growth strong. KT and GA3 showed significant effect on the seed germination,The optimal concentration was 50×10^-6 g·L^-1 for KT, the germination potential of Rheum palmatum seeds can be improved with 0.03% GA₃. Hydrogen peroxide(H₂O₂)and Rare Earth showed no significant effect on the seed germination.2. The Rheum palmatum seeds soaked with suitable concentration of KH₂PO₄ and CaCl₂ ,the activities of protease during seed germination were improved. the seed vigor and germination rate were increased. In particular,the activities of protease and amylase were reached to maximum with the seeds soaked 0.7% KH₂PO₄, root activity of Rheum palmatum seedling during seedlings growth were suppressed with KH₂PO₄, This inhibitory effect could be increased with gradually increase in concentration of KH₂PO₄, the chlorophyll content and activities of superoxide dismutase(SOD)and Catalase (CAT)of Rheum palmatum seedlings during seedlings growth were increased with 0.3%- 0.5% KH₂PO₄. The treatment of CaCl₂ was enhanced the vitality of the seeds by influencing protease activity.the rootactivity,chlorophyll content, SOD and CAT of Rheum palmatum seedlings during seedlings growth were increased with 0.5%CaCl₂.The results indicated that Rheum palmatum seed soaked with CaCl₂ and KH₂PO₄ could accelerate the growth of seedling and promote the breeding of healthy seedling.3. The 1000-grain fresh weight incresed and got at the highest value on the 36th day following blossom, and then rapidly decreased to the level near its dry weight, which fitted to Logistic equation with a rapid increase during 13-36 d after blossom. The grain filling rate showed'fast-slow-fast-slow'pattern. The starch incresed in the'S'curve fitted to Logistic equation with a higher value after 36 d and maintained relative stability to the end, which was greatly affected by weather in cumulation rate. The protein showed'high-low-high'fluctuating. The seed germination vigor, germination rate and germination index were significantly improved with filling duration prolong within 36 d after blossom but showed difference further long. the seed filling is affected by weather. The seeds belong to low-protein type. The stable and higher starch content in seeds is an important indicater for maturation and the maturity affects the seed germination. The best harvest time should be during 46–52 d following blossom (at the beginning of July) during which the water content in the seeds should be 12%-16% with still non-perishing stems. the starch cumulation in the seeds should be about 11.5% .The seeds shoule be harvested in mesh bags to prevent them from falling off their plants and threshed after wind dry.4.the low temperature and water content can maintain the viability and vigour of seeds of Rheum palmatum.With the increase in storage time,the germination rate of Rheum palmatum seeds were lower than new seeds. the germination rate of the old seeds of Rheum palmatum declined to the half of before storage in room temperature after 12 months of storage, the viability and vigour of new seeds is still higher after 6 months of storage, The activities of SOD and CAT were higher than that of old seeds. the germination rate of Rheum palmatum seeds, the germination rate of Rheum palmatum seeds can be improved after low temperature and ultra-dry storage, In particular, ultra-dry storage at low temperature increases significantly improved Rheum palmatum seed germination rate.